According to our current understanding of physics based on the theory of relativity, an object with mass cannot reach or exceed the speed of light. As an object with mass accelerates toward the speed of light, its relativistic mass increases, requiring an infinite amount of energy to actually reach the speed of light. Therefore, it is not possible for a ship with mass to travel at the speed of light.
However, let's explore the scenario hypothetically where a ship could travel at the speed of light. According to the principles of special relativity, time dilation occurs as an object approaches the speed of light. As a result, time for the object in motion would appear to pass more slowly relative to an observer at rest.
From the perspective of an observer on Earth, if the ship were traveling at the speed of light, time would effectively stop for the ship. This means that the ship would appear frozen at its departure point and wouldn't seem to be moving from the observer's frame of reference.
Furthermore, due to the phenomenon of length contraction, the ship itself would appear foreshortened in the direction of its motion. So, from the perspective of the observer on Earth, the ship would also appear compressed or flattened.
Regarding anything leaving or arriving aboard the ship, the situation becomes more complex. Since time appears to stop for the ship, any process or event happening within the ship would also seem frozen or halted to the observer on Earth. This implies that no observable change would occur, and it would appear as if nothing is leaving or arriving on the ship.
It's important to note that this hypothetical scenario of a ship traveling at the speed of light is purely theoretical and not currently possible based on our scientific understanding.